A color image formation apparatus employing an electrophotographic method has been applied not only to office use such as color printers or color copiers, but also to commercial printing fields which are called desk-top publishing (DTP) and on-demand publishing. In the commercial printing fields, the color image formation apparatus employing an electrophotographic method is suitably used as a pre-press apparatus which is employed in the preparatory stages to prepare plates for mass-printing or an apparatus which can perform quick printing of a small lot such as several thousand prints to several ten thousand prints.
In the commercial printing field including a color image, most of corporate colors or colors of logo-marks, trade narks and products do not fall within the color reproduction range of the printing standard color. This means that a corporation or a group has an intention to transfer the message to users through the color, tone which is well refined. Accordingly, when corporate colors, logo marks or trade marks are printed, a specific one so-called a special toner has been often employed.
The special toner provides a brilliant and satisfactory toner image with uniform gloss, however, it requires change of a transporting path and a developing device of the special toner for each of different clients, which greatly increases maintenance time and lowers productivity.
Thus, there is still a difference between the standard color for printing and the discriminative color gamut range. Technique to minimize the difference and obtain a comfortable color image without apparent difference has been developed in the display field such as a television. Typical examples thereof include those disclosed in Japanese Patent O.P.I. Publication Nos. 2000-199982, 2001-312102 and 2006-78926. However, techniques disclosed in these patent documents have problem in that it is difficult to sufficiently present color reproduction to the level as required in the commercial printing field.